The prediction, explanation and modification of individuals' health behavior (e.g., information seeking; taking preventive measures), illness behavior (e.g., seeking medical attention), and sick-role behavior (e.g., adherence to therapeutic regimen) are vital concerns of health practitioners and researchers. One individual difference construct from social learning theory - locus of control beliefs - has been shown to have some promise in predicting and explaining such behaviors. Recently, a health specific measure of this construct has been developed by the principal investigators and has been adopted in a number of studies. The purpose of this project is to develop a set of reliable multidimensional health locus of control (MHLC) scales, to establish their validity, and to demonstrate their applicability in field settings. The dimensions to be studied are: 1) internality - the belief that one's health is under one's own control; 2) chance externality -the belief that one's health is dependent upon luck or fate; and 3) powerful others externality - the belief that other people have power over one's health. A wide variety of behaviors, subject populations and settings will be investigated to establish the usefulness of these dimensions of the locus of control construct measured by the MHLC scales.